I recommend using The Events Calendar's Promoter before you opt for this solution. Promoter should takes care of this feature for you but if you need something more hands-on or customized in a particular way, then I hope this coding snippet can help you get there.
This is a addon to The Events Calendar Ticket plugin
The plugin should remind the user sometime before the event starts.
- CRON jobs - Have a web host or server with this feature
- 3rd Party SMTP like Sendgrid (optional if your server can handle mailing)
- Events Calendar Ticket
Have the Event Reminder in the WordPress Plugin folder and activate